Many electrical fuses, including the fuses employed in automotive vehicles, comprise a pair of generally blade terminals which are electrically connected to one another. The electrical connection between the blade terminals of the fuse is selected in accordance with the specified current to be carried by the circuit into which the fuse is incorporated. An electrical current level which exceeds the specified level will damage the electrical connection between the blade terminals of the fuse, thereby breaking the circuit and preventing more serious damage to other electrical components. The fuse is removably mounted in the electrical circuit such that the fuse can be removed and replaced if the electrical fuse connection between the blade terminals is broken.
Typically the planar blade terminals of the fuse are disposed in spaced generally coplanar relationship. The blade terminals generally are elongated substantially rectangular structures aligned with their respective long axes generally parallel. One longitudinal end of each blade and the electrical connection therebetween typically is mounted in a nonconductive fuse housing. The opposed longitudinal end of each blade terminal extends from the nonconductive fuse housing for insertion into two separate blade receiving terminals which are mounted in a fuse block or similar structure. Thus, the fuse completes an electrical circuit between the two blade receiving terminals in the fuse block. However, upon damage to the electrical connection in the fuse between the fuse terminal blades, the circuit between the two blade receiving terminals in the fuse block is broken.
The above described bladed fuses are widely used in the automotive industry to protect virtually all of the electrically powered equipment of an automobile, including the headlights, sound systems, dashboard indications, air conditioners and such. The entire electrical system, including the fuses are necessarily subjected to very substantial vibrations and extreme ranges in temperature within the automotive environment. Thus, the blade receiving terminals into which the above described bladed fuses are inserted must achieve the seemingly conflicting objectives of providing for removability in the event of damage to the fuse and providing for a high quality electrical connection through all extreme ranges of vibration and temperature.
The prior art terminals for receiving the blade terminals of a fuse typically have been stamped and formed from strips of metal to define opposed terminal contact arms for mechanically and electrically engaging opposed sides of the blade terminals of the fuse. More particularly, the strips of metal have been formed in the prior art terminals such that the major planar surface of the formed metal strip is in face to face contact with one of the planar surfaces of the bladed fuse terminal. This prior art construction is intended to maximize the area of contact between the blade terminal of the fuse and the blade receiving terminal. To improve the contact pressure, the prior art blade receiving terminals have been formed such that the opposed contact arms must be biased away from one another by the insertion of the bladed fuse terminals therebetween.
An example of a typical prior art bladed fuse receiving terminal is shown in U.S. Pat. No. 4,460,239 which issued to Inoue on July 17, 1984. It will be noted that the terminals shown in U.S. Pat. No. 4,460,239 each are formed from a single strip of metal having major length and width dimensions defining opposed major surfaces and having a minor thickness dimension which extends between the major surfaces. A blade receiving slot is defined between two opposed major surfaces of the formed metal strip. One strip of metal defining the blade receiving slot must be resiliently deflected about an axis disposed in or parallel to the plane of the metal to receive the fuse blade in the slot. The resiliency of the metal is then intended to exert a force against the fuse blade terminal mounted in the slot. The formed fuse blade receiving terminal of U.S. Pat. No. 4,460,239 further includes a pair of slots for mounting the terminal to a bussing strip.
A similar prior art fuse blade receiving terminal is shown in U.S. Pat. No. 4,451,109 which also issued to Inoue. The terminal of U.S. Pat. No. 4,451,109 is formed from a single strip of metal and is provided with a pair of slots for mounting the terminal to a bussing strip. A terminal contact arm is bent around an axis disposed in or parallel to the plane of the metal, and is angularly directed toward the bussing strip engaged in the pair of slots. Thus, the terminal shown in U.S. Pat. No. 4,451,109 is operative to urge a blade terminal of a fuse mounted therein against the bussing strip.
Other prior art using fuse blade receiving terminals defined by strips of metal bent around an axis disposed in or parallel to the plane of the metal material are shown in U.S. Pat. No. 4,391,485 which issued to Urani on July 5, 1983; U.S. Pat. No. 4,466,683 which issued to Ballarini on Aug. 21, 1984; U.S. Pat. No. 4,456,274 which issued to Olivera on Dec. 3, 1985 and U.S. Pat. No. 4,560,227 which issued to Bukala on Dec. 24, 1985.
A particularly effective electrical terminal for applications other than fuses is shown in U.S. Pat. No. 4,693,536 which issued to Colleran et al. on Sept. 15, 1987 and which is assigned to the assignee of the subject invention. The terminal shown in U.S. Pat. No. 4,693,536 includes insulation displacement terminal structure at one end and a pin or spade receiving terminal structure at the opposed end. The pin or spade receiving end of the terminal shown in U.S. Pat. No. 4,693,536 is formed from a metallic strip bent about an axis extending parallel to the plane of the metal to define a generally U-shape having a pair of parallel arms and a connecting portion. A pin or spade receiving slot of uniform width along its length extends through the connecting portion of the U-shape and longitudinally through each arm. Thus, the slot shown in U.S. Pat. No. 4,693,536 effectively defines a pair of opposed U-shaped terminal portions which are spaced equal distances from one another along the entire length of the uniform width slot. A plurality of such terminals are mounted in a housing constructed to receive spade or pin terminals at one end and insulated conductors at the opposed end. The terminals are aligned in the housing such that the respective arms of the U-shaped structures lie in two opposed generally parallel planes. The slots in the array of terminals define spaced apart parallel planes, with the number of such planes being equal to the number of terminals. Thus, for example, in an array of two such terminals, the first arms of a first terminal would lie in the same plane as the first arms of a second terminal. Similarly, the second arms of the first terminal would lie in the same plane as the second arms of the second terminal. The slots formed in the two terminals would define two spaced apart generally parallel planes. Although the pin or spade receiving portion of the terminal shown in U.S. Pat. No. 4,693,536 provides desirable electrical connection for many purposes, this terminal is not designed for receiving a blade fuse in the high vibration environments encountered in automotive electronics and does not provide any specific teaching directed to the above described automotive fuses.
In view of the above, it is an object of the subject invention to provide an improved terminal for mating with the blade terminal of a fuse.
It is another object of the subject invention to provide an electrical terminal for achieving superior electrical and mechanical connection to a bladed fuse terminal in a high vibration automotive environment.
An additional object of the subject invention is to provide a plurality of terminals for receiving the blades of an automotive fuse.
Still a further object of the subject invention is to provide a blade receiving terminal for mounting to a printed circuit board and for securely but removably receiving a blade terminal of a fuse.